Sound-box mounting



Jan. 16, 1923.

C4 SCRABIC.

Scum: Bpx MOUNTING ORIGINAL Fl LED MAR 28 1 921 Car/ $rabi Patented Jan.16, 1923c STATES CARL SCRABIC, OF URBANA, OHIO.

SOUND-BOX MOUNTING.

I Application filed March 28, 1921, Serial No. 456,049. Renewed. July10, 1922. Serial No. 573,923.

To all whom it may concern:

Be it known that CARL Somme, a citizen of the United States, residing atUrbana, in the county of Champaign and State of Ohio, has inventedcertain new and useful Improvements in Sound-Box Mountings, of which thefollowing is aispecification.

This invention relates to an improved mounting primarily adapted for usein conjunction with talking machines for the purpose of providing anefiicient connection between the sound box and tone arm members of suchmachines, the construction of the mounting being of such nature as toprovide means whereby the sound box may be securely yet detachablycarried by the outer end of a tone arm; to include a constructionwhereby the metallic parts of the sound box and tone arm will berelatively insulated to eliminate metallic vibration or chattering; toprovide means for sealing the interior chambers of the sound box andtone arm in order that extraneous influences will not interfere with thefree, proper and undisturbed passage of the sound waves through thestructure, and finally and more essentially to provide the mounting withfeatures of construction whereby the sound box will have a verticalpivotal connection with the outer end of the tone arm, in order that thestylus of the sound box may be perfectly centered within the groove ofthe record irrespective of irregularities in the curve characteristicsof the groove, the mounting being 35 such as to normally maintain thecasing substantially at right angles to the outer end of the tone armand yet under abnormal conditions, to permit of the flexing of the soundbox relative to the tone arm to com pensate for the irregularitiesmentioned.

With these and other objects in view, as will appear as the descriptionproceeds, the invention accordingly consists in the novel features ofconstruction, combinations of elements and arrangements of parts, andhereinafter to be fully described and pointed out in the appendedclaims.

In the drawing:

Figure 1 is a vertical sectional view taken through the, improvedcoupling comprising the present invention,

Figure 2 is a side elevation thereof,

Figure 3 is a transverse vertical sectional view taken on the planedisclosed by the line 3-3 of Figure 1,

Figure 4 is a detail perspective view of one end of the tone arm, and

Figure 5 is a similar view of the securin sleeve.

Referring more particularly to the details of the invention, the numeral1 designates a sound box of the type employed in conjunction withtalking machines, and the numeral 2 designates the cooperatively associated tone arm, of the type employed for conducting sound vibrationsset up by the sound box to the usual amplifier construc tion, not shown.The sound box, in this instance, includes an annular metallic casing 3,in which is provided a diaphragm chamber 4L, and the usual vibratorydiaphragm 5 is adapted to be mounted for vibration within the chamber 4and has its peripheral edges disposed for engagement with annulargaskets 6, which enable the diaphragm to vibrate independently of thewalls of the casing, the diaphragm and gaskets being maintained withinthe chamber t by the provision of a removable ring 7. The diaphragm isconnected axially with the offset upper end 8 of an oscillatory stylusmem ber 9 which, in turn, is intermediately pivoted as at 10 to thelower part of the casing 3, the end 8 of the stylus member beingproperly maintained in contact or engagement with the diaphragm 5 bymeans of a spring 11, which operates upon said stylus in such manner asto force the upper end thereof outwardly. The lower end of the stylus isprovided with the usual needle socket 12, in which a needle 13 may beremovably mounted for engagement with the grooves of a record, It willbe understood that in operation the stylus member will be oscillated bythe engagement of the needle with the record undulations, the vibratorymovement thereof will be imparted to the diaphragm 5 in the usualmanner, and the sound wave set up by the vibration of the diaphragm willthen, in turn, be transmitted to the communicating end of the tone arm2, which end is designated by the numeral let, in this instance isdisposed to enter the rear side of the casing 3 centrally and axiallythrough an opening 15 provided therein, in order to be in opencommunication with the chamber 4. It will be understood that the soundwaves are thence conducted by the tone arm to suitable amplifying beams.

The present invention'aims to provide an improved mounting or couplingfor connecting the casing of the sound box with the end 1% of the tonearm, and to effect this result in such manner that while the casing willbe securely mounted in connec tion with the tone arm yet there will beno positive and direct metallic contactbetween the casing proper and thetone arm. This end effected by forming the end isof the tone arm with afixed collar 16 which is slightly spaced from the extreme outer portionof the end 1%. The periphery of this collar is provided with a pair ofoutwardly projecting studs 17, preferably, of substantially triangularformation. These studs are adapted to be positioned within bayonet slots18 provided in a metallic sleeve 19 arranged to be rigidly carried bythe rear wall of the casing 3, the interior of said sleeve being of adiameter slightly exceeding that of ti e collar 16, in order that saidcollar may be received within the sleeve. The sleeve 19, in thisinstance, is formed at one end with a laterally projecting annularflange 20, which is designed to engage with a flat annular gasket 21.,which is arranged to be interposed between the flange 20 and the rearwall 22 of the casing 3. Fastening elements, in the nature of screws orthe like 23 are arranged to pass through the flange 20, the gasket 21and to be threaded into the wall 22, in order that the sleeve 19 may berigidly mounted in connection with the using 3 and to be maintained in aconcentric position with respect to the longitudinal axis of said casingand the end 1 of the tone arm 2, the gasket 21 being utilized to avoiddirect contact between the metallic wall of the casing and the flange20, thus to prevent sympathetic vibration between these ordinarilymetallic parts. Arranged to be positioned between the gasket 21 and theinner wall of the collar 16 is a compressible ring 24L, of rubber or thelike, which is so positioned that when the studs 17 have been passedthrough the entrances 25 of the slots 18 and thence into thecircumferentially extending portions 26 of said slots, the said ring 2will be more or less compressed, thus exerting an outward ly directedpressure on the sound box proper. Therefore, when the sound box has beenrevolved to its maximum extent, the said studs 17 will be seated withinthe relatively enlarged and closed inner ends 27 of the slots, and willbe maintained therein by the resiliency of the ring 24, so that the saidstuds will be retained within the ends in order to lock the sound. boxin its position of application upon the end of the tone arm. Anothergasket ring 20 is positioned in the oute' end of the sleeve 19 andengages with one face of the collar 16 so as to close the outer end ofthe sleeve and to prevent undue sound vibration therein.

In view of the foregoing description, when taken in conjunction with theaccom panying drawing, it will be apparent that the present inventionprovides a novel and efficient mounting or coupling between the soundbox oi? a talking machine and the cooperating end of a tone arm. It willbe observed that the construction will admit of the convenientpositioning of the sound box upon the end of the tone arm and to securethe same in connection therewith, the construction also serving toeliminate screws or other similar fastening elements. More essentially,however, the coupling avoids direct metallic contact between the casingof the sound box and the companion parts of the tone arm and thusovercomes such undue vibration and interference with sound reproductionas will occur when metallic parts are directly and physically connectedin engagement with one another.

It will be observed that the provision of the radially extending,vertically disposed knife edges provided by the stud 17, will produce avertical pivotal connection between the sound box and the outer end ofthe tone arm, which will permit of change in the angular relationshipexisting therebetween, Normally, the sound box casing will be positionedsubstantially at right angles to the longitudinal axis of the outer endof the tone arm, and the compressible ring 24 will normally serve, byreason of its confined position, to maintain this relationship betweenthe arm and the sound box casing proper. However, in the event that thestylus of the sound box is traveling in a record groove of irregular orabnormal formation, the sound box is permitted to swing to a limiteddegree by reason of the studs 17, in order that said sound box may haveits stylus centrally positioned within the record groove so as toovercome undue friction between the walls of the groove and the stylus,and to thus enable the sound box to faithfully reproduce the soundundulations provided in arecord groove. It will be understood that whenthe turning or twisting pressure upon the sound box has been removed,the ring '24 will automatically serve to return the sound box casing toits normal position.

What is claimed is:

1. In a talking machine, a sound box casing, an axially located sleeverigidly carried by and projecting from the back of said casing, a tonearm disposed axially within said-sleeve, a collar formed with said tonearm and positioned within said sleeve, diametrically opposedstuds-projecting from said collar and received within bayonetslotsformed in saidsleeve, and resilient means interposed between said collarand casing and serving to oppose the turning movement of said casingupon said studs.

2. In a talking machine, a sound box casing, a sleeve mounted upon theback wall of said easing and projecting axially therefrom, a tone armarranged to be axially received Within said sleeve, a Wall formed withsaid tone arm, studs having knife edges projecting from said well andarranged to be received within bayonet slots provlded in said sleeve,and eompresslbie means located between said well and said casing andserving to resist turning movement of said caslng about said studs.

In testnnony whereof I affix mv slegnature.

CARL sesame.

